In this study, we describe a methodology to examine dislocation loops in irradiated steels based on a combination of crystallographic information and g⋅b invisibility criteria. Dislocation loops in transmission electron microscope (TEM) images can be conveniently analyzed using this method. Through this analysis approach, dislocation loops in reduced activation ferritic/martensitic (RAFM) steels irradiated at 400°C have been examined. The predominant types of loops found in irradiated RAFM steels were 〈100〉{200} and 1/2〈111〉{111}. The size, density, and density anisotropy of these two types of dislocation loops were quantified. It was observed that the 〈100〉{200} loop density is more than twice that of 1/2〈111〉{111} loops. A large density anisotropy of 〈100〉{200} loops was identified.